1. Field of the Invention
The invention is directed at novel polymeric electrolye-hydrogen peroxide adducts and mixtures of adducts with selected bleach precursor compounds. These materials are useful for bleaching laundry and hard surfaces.
2. The Related Art
Commercially the most common source of dry peroxide is that available in the form of sodium perborate tetrahydrate or monohydrate. Perborate is a material within the class of peroxyhydrates which are mixed salts of inorganic or organic acids forming peroxide containing compositions through hydrogen bonding. Perborate is somewhat special among these materials in that the peroxide is bound chemically as the cyclic diperoxy anhydride of boric acid rather than a comparatively weaker hydrogen bonded peroxyhydrate. Although the inorganic perborates are widely available at economical prices, by themselves they are inefficient bleaches.
A number of patents have reported dry organic hydrogen peroxide sources. U.S. Pat. No. 3,929,875 (Rapko et al.) discloses ethane tetracarboxylate perhydrates having a 1:4 ratio of peroxide to carboxylate. U.S. Pat. No. 4,279,769 (Yagi et al.) reports a bleaching composition of tetrasodium ethane tetracarboxylate/hydrogen peroxide adduct in combination with a class of carboxyimino compounds. Polycarboxylates and/or sulfonate such as disodium diglycolate were reported in U.S. Pat. No. 4,655,975 (Snoble) to form peroxyhydrates which could serve as a solid source for hydrogen peroxide. All the organic peroxyhydrates of the foregoing art provide additional building benefits over current common commercial peroxygen sources, especially in comparison to perborates and urea peroxyhydrate. Unfortunately, the materials reported in these patents are typically of lower oxygen activity. Larger doses are therefore required to deliver equivalent performance. Not only is there an economic penalty but the greater proportion required cuts down on the formulation space thereby hindering formulation flexibility. Moreover, the methods by which these peroxyhydrates are formed require mild processing conditions and, especially, low temperatures to avoid decomposition.
Several patents have focused upon stable liquid hydrogen peroxide bleach systems. U.S. Pat. No. 4,079,015 (Paucot et al.) discloses a liquid composition of hydrogen peroxide, a surfactant, and a salt of a polymer derived from an alpha-hydroxyacrylic acid. With this composition there is achieved stability against phase separation and reduced oxygen loss. DD 252 378 A1 (Lehmann et al.) is somewhat similar disclosing polymeric percarboxylic acids. Another patent, U.S. Pat. No. 4,772,290 (Mitchell et al.), discloses laundry bleaching compositions containing a dispersion of solid particulate peracid activator in an acidic aqueous hydrogen peroxide media.
A problem with the polymeric percarboxylic acids is the difficulty in achieving complete peroxidation. Normally there would be a very low ratio of peracid to each potentially available carboxylate group. Thus, there again arises the need for incorporating large dosages rendering the formula uneconomic and constricting the remaining room for other desirable formulation components.
Accordingly, it is an object of the present invention to provide a solid peroxyhydrate capable of delivering economic levels of active oxygen.
Another object of the present invention is to provide peroxyhydrates having improved storage stability.
A still further object of the present invention is to provide a peroxyhydrate that delivers high levels of active oxygen yet requires a low dosage level in a product formulation.
Yet another object of the present invention is to provide a peroxyhydrate that would not only deliver bleach performance but exhibit calcium sequestration and dispersant properties.
These and other objects of the present invention will become more readily evident in light of the following detailed description.